I agree with your premise, but from what I heard the union leader didn't give a fuck. He said he wanted to speak at the DNC as well and went on about how nobody is helping the workers and they only help corporations.
Here's a write up and video(there's a link to the actual speech)
Labor law must be reformed. Americans vote for a union, but can never get a union contract. Companies fire workers who try to join unions and hide behind toothless laws that are meant to protect working people but are manipulated to benefit corporations. This is economic terrorism at its best, an individual cannot withstand such an assault.”
At this point, I'm almost convinced they purposefully gave him the chance to take his shot.